The packaging of hydrophilic contact lenses in a sterile aqueous solution is well known in the contact lens manufacturing technology. In particular, such packaging arrangements generally consist of so-called blister packages which are employed for the storage and dispensing of hydrophilic contact lenses by a medical practitioner or a consumer who intends to wear the contact lenses. Generally, such hydrophilic contact lenses, which may be disposable after a single wear or short-term use, are manufactured from suitable hydrophilic polymeric materials, such as hydroxyethyl methacrylate (HEMA). Generally, such contact lenses must be stored in a sterile aqueous solution, usually in isotonic saline solution in order to prevent dehydration and to maintain the lenses in a ready-to-wear condition.
Heretofore, contact lens manufacturers normally utilized stoppered glass bottles containing sterile saline solutions in which the hydrophilic contact lenses were immersed. Each bottle was sealed with a suitable silicone stopper and provided with a metal closure as a safety seal in the configuration of an overcap. When the contact lens was intended to be removed from the bottle for use by a patient, the metal closure safety seal was required to be initially torn off the bottle, thereafter the stopper withdrawn and the lens lifted out from the bottle through the intermediary by a suitable tweezer or by pouring the contents from the bottle. This entailed the implementation of an extremely complicated procedure, since the contact lens was difficult to grasp and remove from the saline solution contained in the bottle due to the transparent nature of the contact lens which rendered it practically invisible to the human eye.
More recently, containments in the form of blister packages have been developed for hydrophilic contact lenses, and which enable the storage and shipping of the hydrophilic contact lenses in a simple and inexpensive expedient manner, while concurrently facilitating the removal of the contact lens by a practitioner or a patient.
For instance, a blister package which is adapted to provide a sterile sealed storage environment for a disposable or single-use hydrophilic contact lens, wherein the lens is immersed in a sterile aqueous solution, for example, such as in an isotonic saline solution, is described in Martinez, U.S. Pat. No. 4,691,820. Additional contact lens packages are disclosed in U.S. Pat. Nos. 4,691,820; 5,054,610; 5,337,888; 5,375,698; 5,409,104; 5,467,868; 5,515,964; 5,609,246; 5,620,088; 5,695,049; 5,697,495; 5,704,468; 5,711,416; 5,722,536; 5,573,108; 5,823,327; 5,704,468; 5,983,608; 6,029,808; 6,044,966; and 6,401,915.
Contact lens packages are typically formed from hydrophobic packaging materials, such as polypropylene, polyethylene, nylons, olefin co-polymers, acrylics, rubbers, urethanes, polycarbonates, and fluorocarbons.
Silicone hydrogel contact lenses (i.e., contact lenses which comprise a silicone hydrogel material or a hydrophilic silicon containing polymer) can be stored in packages formed of hydrophobic packaging materials. However, since silicone hydrogel contact lenses are typically made of hydrophobic materials, the contact lens will often stick or adhere to the packaging material when a surface of the contact lens and a surface of the packaging material contact. The sticking of the silicone hydrogel contact lens to the package causes many problems, including an increased chance that the lens will tear when removed from the package.
To attempt to reduce the tendency for silicone hydrogel contact lenses to stick to hydrophobic packaging materials, surfactants have been added to the contact lens packaging solution, see U.S. Patent Pub. No. 2005/0171232. Not all surfactants achieve the desired reduced tendency to stick, and some surfactants do not dissolve completely in the lens packaging solution and/or distort certain properties of the lenses.
Another attempt at reducing the tendency for silicone hydrogel contact lenses to stick to hydrophobic packaging materials is to physically or structurally alter the bottom surface of the package cavity. For example, certain packages have been produced that comprise one or more ridges or one or more grooves on the bottom surface of the cavity.
Thus, there remains a need for improved contact lens packages, particularly, contact lens packages that are suitable for storage of lenses, for example, silicon-containing polymeric contact lenses.